Given the priority for population dietary change there is a need for a greater understanding of the determinants that affect food choice. This review examines the major influences on food choice with a focus on those that are amenable to change and discusses some successful interventions.

1. Major determinants of food choice

The key driver for eating is of course hunger but what we choose to eat is not determined solely by physiological or nutritional needs. cooking) and time

Social determinants such as culture, family, peers and meal patterns

Psychological determinants such as mood, stress and guilt

Attitudes, beliefs and knowledge about food

The complexity of food choice is obvious from the list above, which is in itself not exhaustive. Food choice factors also vary according to life stage and the power of one factor will vary from one individual or group of people to the next. Thus, one type of intervention to modify food choice behaviour will not suit all population groups. Rather, interventions need to be geared towards different groups of the population with consideration to the many factors influencing their decisions on food choice.

1.1 Biological determinants of food choice

Our physiological needs provide the basic determinants of food choice. Humans need energy and nutrients in order to survive and will respond to the feelings of hunger and satiety (satisfaction of appetite, state of no hunger between two eating occasions). The central nervous system is involved in controlling the balance between hunger, appetite stimulation and food intake. carbohydrates, proteins and fats generate satiety signals of varying strength. The balance of evidence suggests that fat has the lowest satiating power, carbohydrates have an intermediate effect and protein has been found to be the most satiating (Stubbs et al. 1996).

The energy density of diets has been shown to exert potent effects on satiety; low energy density diets generate greater satiety than high energy density diets. The high energy density of high fat and/or high sugar foods can also lead to ‚passive overconsumption‘, where excess energy is ingested unintentionally and without the consumption of additional bulk.

An important satiety signal may be the volume of food or portion size consumed. Many people are unaware of what constitutes appropriate portion sizes and thus inadvertently consume excess energy.

Palatability is proportional to the pleasure someone experiences when eating a particular food. It is dependent on the sensory properties of the food such as taste, smell, texture and appearance. Sweet and high fat foods have an undeniable sensory appeal. It is not surprising then that food is not solely regarded as a source of nourishment but is often consumed for the pleasure value it imparts.

The influence of palatability on appetite and food intake in humans has been investigated in several studies. There is an increase in food intake as palatability increases, but the effect of palatability on appetite in the period following consumption is unclear. Increasing food variety can also increase food and energy intake and in the short term alter energy balance (Sorensen et al. 2003). However, effects on long term energy regulation are unknown.

‚Taste‘ is consistently reported as a major influence on food behaviour. In reality ‚taste‘ is the sum of all sensory stimulation that is produced by the ingestion of a food. This includes not only taste per se but also smell, appearance and texture of food. These sensory aspects are thought to influence, in particular, spontaneous food choice.

From an early age, taste and familiarity influence behaviour towards food. A liking for sweetness and a dislike for bitterness are considered innate human traits, present from birth (Steiner 1977). Taste preferences and food aversions develop through experiences and are influenced by our attitudes, beliefs and expectations (Clarke 1998).

1.2 Economic and physical determinants of food choice

There is no doubt that the cost of food is a primary determinant of food choice. Whether cost is prohibitive depends fundamentally on a person’s income and socio economic status. Low income groups have a greater tendency to consume unbalanced diets and in particular have low intakes of fruit and vegetables (De Irala Estevez et al. 2000). However, access to more money does not automatically equate to a better quality diet but the range of foods from which one can choose should increase.

Accessibility to shops is another important physical factor influencing food choice, which is dependent on resources such as transport and geographical location. Healthy food tends to be more expensive when available within towns and cities compared to supermarkets on the outskirts (Donkin et al. 2000). However, improving access alone does not increase purchase of additional fruit and vegetables, which are still regarded as prohibitively expensive (Dibsdall et al. 2003).